Conventionally, a digital signal reproducing circuit used with a digital audio tape recorder having the DASH format equalizes the continuous analog waveform of a reproduced digital signal obtained from the reproducing head and reproduces the signal from which DC is removed. All of these circuits are composed of analog circuits, in view of the processing speed that is required.
When the digital signal reproducing circuit is adjusted, various kinds of large measuring instruments and skilled workers are needed and thus it is contemplated that a manufacturing process and adjustment process can be greatly simplified if this adjustment can be automatically executed.
Nevertheless, since the digital signal reproducing circuit is composed of analog circuits as described above, the realization of the automatic adjustment thereof is very difficult, so long as the analog circuits are used, from the view point of the circuit arrangement, number of components in use, items to be adjusted, and cost.